CVE-2019-5785 in Chrome
Summary
by MITRE
Incorrect convexity calculations in Skia in Google Chrome prior to 72.0.3626.81 allowed a remote attacker to perform an out of bounds memory write via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/26/2024
The vulnerability identified as CVE-2019-5785 represents a critical memory safety issue within the Skia graphics library component that forms part of Google Chrome's rendering engine. This flaw exists in versions prior to 72.0.3626.81 and demonstrates how mathematical miscalculations in graphics processing can lead to severe memory corruption vulnerabilities. The Skia library serves as a core component responsible for 2D graphics rendering across Chrome's user interface and web content processing, making it a prime target for exploitation.
The technical root cause of this vulnerability stems from incorrect convexity calculations within the Skia graphics library's polygon processing algorithms. When Chrome encounters HTML content containing specially crafted graphical elements, the flawed convexity determination logic fails to properly validate memory boundaries during polygon triangulation operations. This mathematical error creates a condition where the rendering engine attempts to write data beyond the allocated memory buffer, resulting in an out of bounds memory write operation. The vulnerability specifically manifests during the processing of complex graphical elements that require convex hull calculations for proper rendering.
Remote attackers can exploit this vulnerability by crafting malicious HTML pages that contain carefully constructed graphical elements designed to trigger the flawed convexity calculation path. When a user visits such a page, Chrome's rendering engine processes the malicious graphics code, causing the memory corruption to occur in the graphics memory space. This type of exploitation falls under the category of remote code execution vulnerabilities, as the out of bounds write can potentially be leveraged to overwrite critical memory locations and execute arbitrary code. The vulnerability demonstrates how graphics rendering components can serve as attack vectors for memory corruption exploits, similar to patterns seen in other graphics-related vulnerabilities.
The operational impact of CVE-2019-5785 extends beyond simple memory corruption, as it represents a significant risk to user security and system integrity. This vulnerability is particularly dangerous because it can be triggered through standard web browsing activities without requiring any special user interaction beyond visiting a malicious website. The exploitability of this flaw means that attackers can potentially gain full control over affected systems, making it a high-priority security concern. The vulnerability affects all users of affected Chrome versions and requires immediate patching to prevent exploitation. This issue aligns with ATT&CK technique T1059.001 for remote code execution through web-based attacks and follows CWE-787 pattern for out-of-bounds write conditions in graphics processing components.
Mitigation strategies for this vulnerability center on updating to Chrome version 72.0.3626.81 or later, which contains the necessary fixes for the convexity calculation logic. Organizations should implement immediate patch management procedures to ensure all affected systems receive the update. Additional protective measures include implementing browser security features such as sandboxing and content security policies, though these provide only partial protection against this specific class of vulnerability. The fix implemented by Google addresses the core mathematical error in the convexity calculation algorithm and includes proper bounds checking to prevent memory corruption during graphics rendering operations. Security teams should monitor for any related vulnerabilities in graphics libraries and maintain awareness of similar issues that may affect other components using the same underlying mathematical algorithms. This vulnerability serves as a reminder of the critical importance of proper memory validation in graphics rendering components and highlights the need for rigorous testing of mathematical algorithms in security-sensitive software.